HA'GER, Albert David (1817-88). An American geologist, born in Chester, Vt. Having obtained a common-school education, he was appointed assistant naturalist of Vermont in 1856, assistant State geologist under Edward Hitchcock from 1857 to 1861, State geologist from 1861 to 1870, and Vermont Commissioner to the Paris Exposition of 1867. From 1870 to 1877 he was State geologist of Missouri, and in the latter year was appointed librarian of the Chicago Historical Society. He published Geology ofVermont (2 vols., 1861, with Prof. Edward Hitchcock) and other reports of surveys in his native State and in Missouri.